Touchscreen control for a Reprap

After you’ve got your Reprap running smoothly with acceptable resolution and good quality prints, the next order of business for any 3D printer hobbyist is headless printing. While the greatest and newest 3D printers come with controls to allow jogging, homing, temperature control, and printing from an SD card, the home-built versions will require an add-on attached to the electronics board. [Marco] has been spending his time improving the character LCD control panel projects we’ve seen for Repraps with an awesome graphical version that emulates the control interface found in the Pronterface control software.

The biggest problem with adding a control interface to a Reprap is the number of pins available on the electronics board. While an electronics board like RAMPS has enough spare I/O pins to drive a display, other boards such as the Sanguinololu and the Melzi are extremely limited in their expansibility. To get around this limitation, [Marco] used a 4D Systems serial touchscreen display.

This display only requires two pins to fully interact with a printer running the Marlin firmware; the graphical processing, communication, and SD card access is handled by the on-board PICASO micocontroller, leaving the ATMega on the electronics board free for important things like printing stuff out of plastic.

Using an Android tablet is not currently possible as it a) can not communicate with the printer or b) slice files. I don’t see the point in doing “basic” modeling standing in front of the printer, either, when one can sit down on a real PC and do real modeling.

Most android tablets have at least USB-OTG and 4.0+ recognises FTDI leads out of the box. However a better solution is to get a cheep bluetoothTTL serial converter off ebay.
The are many serial/bluetooth terminals in the market, but here is my hacked together host (be careful with the heater sliders):https://zi.is/p/browser/DroidRap
I couldn’t get Slic3r compiling with NDK, so this dose need root access to slice (but everyone on HaD has rooted their phone right?). The was also HaD post of a working port of Skeinforge.
TrueSculpt is fun and Spacedraw is very impressive, but modelling isn’t really feasible. However being able to download and slice a STL is very useful.

I actually worked with one of these displays a few years ago.
It was like pulling teeth. The serial connection uses an oddball pin (DTE I think) for programming, so you can’t use a standard FTDI cable. And if you didn’t hook it up (or a wire came loose), you brick the device. 4D systems is no bloody use at all when it comes to support, so have fun there. Even with the 4D serial converter, programming sometimes worked, and sometimes didn’t, and we still don’t know why.

I think its really cool somebody finally did this. It is the next step after my quite successful LCD+SD interface.
However, I don’t really understand why one needs a dedicated firmware on the 4d. I would have tried to do it by the script files that you can put on the displays sd card.
Also, I think that there is too much stuff on the display at once, and hence, because of the minuscule size of the display it might be hard to push the right stuff without a pen.
Also, I am a bit scared that the additional serial interrupt in the AVR board might cause additional hiccups in the step generation. Already the primary serial needs some serious hacking in the stepper ISR.
Also, I think that moving the head “manually” electronically is not necessary, just disabling steppers and grabbing the head is more intuitive. Also, it takes a tremendous amount of screenspace. Only Z is necessary, because there are lead screws and not pullies.

If everything works smoothly, congratulations, that is awesome.

Anyhow, if there is somebody out there who wants to help porting Marlin to the DUE, please contact me..

I replaced my Reprapdiscount Smart LCD with this last night….completely love it. I’m wondering though if I could use both Smart LCD and this at the same time…The Smart LCD seemed to have more direct access to firmware values I could change on the fly to adjust my print which was great. All of the 4D Systems displays are amazing!